Screw propeller mounting



Sept. 22, 1959 L. COSTA SCREW PROPELLER MOUNTING Filed Oct. 12, 1954INVENTOR Z50 COST/I United States Patent SCREW PROPELLER MOUNTHNG LeoCosta, Vigo, Spain, assignor of one-half to Erich R. F. Maier, Geneva,Switzerland Application October 12, 1954, Serial No. 461,861

Claims priority, application Germany May 5, 1954 3 Claims. (Cl. 115-34)The invention relates to vessels, and more particularly toscrew-propelled vessels.

It is an object of the present invention to improve the propel-lingmeans and/or maneuverability of screwpropelled vessels.

It is another object of the invention to smooth the wake produced by thepropeller.

It is a further object of the present invention to fill up the caveformed in the water directly behind the propeller.

Other objects and advantages of the invention will become apparent fromthe following detailed description thereof in connection with theaccompanying drawings showing, by way of example, some embodiments ofthe present invention. In the drawings Fig. 1 is a diagrammatic sideelevation of an embodiment of the invention, and

Fig. 2 is a diagrammatic side elevation of another embodiment of thepresent invention.

Referring now to the drawings and first to Fig. 1, a bulb 1 is attachedto la fin-like supporting arm 2 which in turn is supported by the hull 3of a vessel or ship. The supporting arm 2 occupies the space directlybehind the propelling screw 4 of the vessel which screw has a cap-likepart 5 capable of rotating in recess 6 of the bulb 1. A rudder blade 7is attached swingably about an axle 8 projecting below the hull 3. Aspointed out, the supporting arm 2 is in the form of a fin andstreamlined and the bulb 1 attached to the supporting arm 2 increasesthe steadiness of the course imparted to the vessel by the rudder blade7. The supporting arm 2 is provided with an extension 9 below thebulb 1. The arrangement thus includes a propeller 4 having a hubportion, said propeller being mounted on the ship for rotation about ahorizontal axis. The rudder is swingably mounted on the ship aft of thepropeller tor rotation about a vertical axis while the bulb-shaped body1 is attached intermediate the propeler and the rudder in coaxialalignment with the horizontal axis of rotation. The fin or mountingmeans 2 interconnect the bulb 1 and the ship for holding the iormer in apredetermined relationship to the propeller and the rudder and forpreventing rotation of the bulb around the horizontal axis. It will benoted that the bulb 1 is of slender streamline shape and increasesrapidly in diameter from its forward end rearwardly to an intermediatepoint and from the intermediate point tapers rearwardly to its rear end.It will furthermore be noted that the axial length of the bulb is atleast twice the length of its largest diameter while the forward end ofthe bulb is blunt and substantially wider than the hub portion of thepropeller. The provision of the recess 6 in the bulb results in the factthat the blunt forward portion of the bulb and the hub are inoverlapping engagement with each other.

Due to this arrangement the vortices produced by the blades 4 of thepropeller and consisting mainly of air and turbulent water will be ledundisturbed backwards along the surface of the bulb 1.

Referring now to Fig. 2 of the drawings an embodiment is shown in whichthe hull 30 of the vessel or ship carries a revolving propeller 40having a cap-like part 50 projecting into a recess 60 of a bulb 10arranged fixedly on a rudder post 12 which latter is rigidly supportedby the hull 30. The rudder is arranged for swiveling motion about theshaft thereof. The rudder post 12 is provided with extensions 13 and 14engaging the shaft 80 so that the rudder 70 can be imparted angulardisplacements.

I wish it to be understood that I have described hereinabove a screwpropelled vessel in several embodiments thereof and that variousmodifications of the described invention will be obvious to any personskilled in the art.

I claim:

1. A propulsion and steering arrangement for a ship, comprising incombination: a propeller including a hub portion, said propeller beingmounted on said ship for rotation about a horizontal axis, a rudderswingably mounted on said ship aft of said propeller for rotation abouta vertical axis, a bulb-shaped body arranged intermediate said propellerand said rudder in coaxial alignment with said horizontal axis ofrotation, and mounting means rigidly interconnecting said bulb-shapedbody and said ship for holding said bulb-shaped body in a predeterminedrelationship to said propeller and said rudder and for preventingrotation of said bulb-shaped body around said horizontal axis, saidbulb-shaped body being of slender stream line shape and increasingrapidly in diameter from its forward end rearwardly to an intermediatepoint and from such intermediate point tapering rearwardly to its rearend, the axial length of said bulb-shaped body being at least twice thelength of its largest diameter, and the forward end of said bulb-shapedbody being blunt and substantially wider than said hub portion, saidblunt forward end and said hub portion being in overlapping engagementwith each other.

2. In an arrangement as claimed in claim 1, said blunt forward end ofsaid bulb-shaped body having a recess, and said hub portion of thepropeller projecting into said recess, whereby said blunt portionembraces said hub portion.

3. In an arrangement as claimed in claim 1, said mounting meanscomprising a fin-like element extending vertically from said ship.

References Cited in the file of this patent UNITED STATES PATENTS1,549,564 Slocum Aug. 11, 1925 1,837,896 Costanievich Dec. 22, 1931FOREIGN PATENTS 385,607 Great Britain Dec. 19, 1932 674,849 Germany May5, 1939 721,041 Germany May 22, 1942 449,307 Italy July 11, 1949 OTHERREFERENCES British Motor Ship, July 1953, pages 162 and 163. See articleentitled, The Cost-a Propulsion Bulb. (Copy in 114-162.)

